Friction draft-rigging



Patented Oct. 7, 1919.

T. H. SYMINGTON. FRICTION DRAFT RlGGING.

APPLICATION FILED NOV. 8. 19!

4 SHEETS-SHEET I.

T. H. SYMINGTONF FRICTION DRAFT RIGGING.

APPLICATION FILED NOV.8.19\I.

1,318,186. Patented 001. 7,1919,

' 4 SHEETS-SHEET 2.

ull/knees /Z (5% 17 W1 T. H. SYMINGTONQ FRICTION DRAFT RIGGING.

APPLICATION FILED NOV. 3. i911.

1,3 18,1 86. Patented Oct. 7, 1919.

4 SHEETSSHEET 3- T. H. SYMINGTON.

FRICTION DRAFT RIGGING.

APPLICATION FILED Nov. 8 19H.

Patented Oct. 7,1919.

4 SHEETS-SHEET 4- if g;

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UNITED STATES PATENT OFFICE.

THOMAS H. SYMINGTON, OF BALTIMORE, MARYLAND.

FRICTION DRAFT-RIGGING.

Application filed November 8, 1917.

T 0 all whom it may concern:

Be it known that I, THOMAS H. SYMING- TON, a citizen of the United States, residing at Baltimore, State of hlaryland, have invented certain new and useful Improvements in Friction Draft-Rigging; and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to draft rigging for railway cars, and more particularly to that type of mechanism commonly called friction draft rigging. The principal object of my invention, broadly stated, is to provide a friction draft rigging of the barrel type which has a high shock absorbing capacity and a free release action. To this end the main features of the invention comprise a friction barrel or shell, a plurality of wedging friction shoes, a plurality of wedging blocks, and means whereby the wedging blocks are forced into wedging contact with the friction shoes to thereby maintain the latter in frictional engagement with the friction barrel. The said means is adapted to evenly distribute the pressure from the wedging blocks over the entire exterior surface of the said friction shoes.

There are other features of the device, as will more clearly appear from the more detailed description of the same when taken in connection with the accompanying drawings which have been chosen to illustrate my invention and in which Figure 1 is a central longitudinal section of a friction draft rigging constructed in accordance with my invention.

Fig. 2 is a half end elevation and half vertical section of the device shown in F ig. 1.

Fig. 3 is a vertical section on line 33 of Fig. 1, some of the wedging blocks being omitted to more clearly show the construction.

Fig. 4 is a partial longitudinal section of the device shown in Fig. 1, some ofthe friction shoes being omitted to show the construction of the spreader member. I

Fig. 5 is a perspective view of one form of spreader member.

Fig. 6 is a perspective view of one of the friction shoes.

Fig. 7 is a detail view showing a slight Specification of Letters Patent.

Patented Oct. '7, 1919.

Serial No. 200,946.

modification in the construction of the fric- V with a slightly tapering interior friction.

surface 2. In the form illustrated in Figs.

1 to 1 and 10, the barrel 1 is provided adj acent th forward end with a cylindrical flange, collar or ring 3 which partially closes the forward or open end .l of the said barrel. This iiange 3 may be formed integral with the barrel 1, as shown in these figures, or may be separate from and attached to the barrel as illustrated in Fig. 7, which will be hereinafter more fully described. The inner end of the barrel 1 is adapted to be closed by a plate 5 which is preferably attached to the barrel 1 by means of a plurality of bolts 6 and cotters 7, the bolts 6 being adapted to pass through openings 8 in the plate 5 and through alined openings 9 which are provided in the ears 10 which project outwardly from the barrel 1. The ears 10 preferably contact with the adjacent sideof the plate 5 which may be as shown of rectangular form, and which may, and preferably does, form the rear follower. It will be readily apparent to those skilled in the art to which this device relates that should it be found desirable, a small amount of play could be permitted between the barrel 1 and the plate 5 to thereby obtain a free or preliminary compression of the cushioning mechanism before the friction mechanism is brought into action.

, The friction mechanism which cooperates with the interior friction surface of the barrel preferably comprises a plurality of segmental wedging friction shoes 12. In the form of the device illustrated six of these shoes 12 are employed. Each of the shoes is provided with a curved or rounded, and preferably slightly tapering, outer friction face 13 to engage the correspondingly formed surface 2 of the friction barrel.

, adapted to seat on and contact with the correspondingly formed face 15 at the rear of the friction shoes.

A spreader member preferably composed of a plurality of oppositely disposed spreading blocks 20 is provided, these blocks being located intermediate the sets of wedging blocks 16 and 17. Each of the spreader blocks 20 is provided adjacent the approximate wedge block with a plurality of con verging wedging seats or faces 21 which conform to and are adapted to coact with the faces 22 of each of the wedge blocks 18. is will be clearly seen from Fig. 3, the face 1-1 on each friction shoe 12, in conjunction with the adjacent faces or seats 21 on the spreader block 20, forms a hollow tetrahedron for the reception of a correspondingly formed wedge block 18. It will be noted, however, each wedge block 18 is of larger dimensions than the hollow tetrahedron formed by the faces of the friction shoes and adjacent faces of the spreader blocks. The forward or outer faces 23 of the wedge blocks in the set 16 are adapted to bear on the inner face 2% of a plunger 25. This plunger is provided with a circular flange or shoulder 26 which is, in the normal or iiioperative position of the device, adapted to engage the inner face of the flange or collar 3 of the friction barrel. The central portion 27 of the plunger 25 extends through the opening of the friction barrel 1 and is adapted to normally contact with the usual follower plate.

The rear faces 23 of the set 17 of wedging blocks are adapted to engage a ring washer or plate 28 which in turn bears against the forward ends of the cushioning springs, which preferably comprise an outer spring 29 and an inner spring 30.

In the form of mechanism illustrated in Figs. 1 to 4: and 10 the springs 29 and 30 are adapted to bear at their inner ends against the forward face of the plate 5, and in this form of device the included parts of the friction mechanism are adapted to be inserted in the rear and slid forwardly in the barrel until the ring 26 on the plunger 25 contacts with the rear face of the flange or collar 3.

In the alternative form illustrated in Fig. 7, the forward end of the barrel 1 is formed by a removable plate 81 which is connected to the barrel by means of a plurality of bolts 6 similar to the bolts 6 hereinbefore described. The heads of the bolts 6 are received in countersinks in the end plate 31.

Each of the bolts is adapted to extend through alined openings 8 in the plate 31 and 9 in the projection 10 formed on the friction barrel l These bolts are preferably held in position by means of cotters 7.

The plate 31 is provided with an opening 32 which is slightly smaller than the internal diameter of the friction barrel 1 whereby said plate forms a ring or collar 33 against which the flange 26 on the plunger 25 may engage, as hereinbefore described. In this form of construction it will be understood that the barrel 1 is, or may be, provided with a closed or integral rear end and that the internal friction members are to be inserted into the barrel from the forward or open end of the same before the plate 31 is applied.

In the form of device illustrated in Fig. 10 a slight modification of the spreading mechanism is shown. In this form the spreading mechanism comprises a plurality of sets of diamond-shaped blocks 3% each of which is provided at one end with oppositely directed wedging faces The adjacent ends 36 of each set of blocks 3% are preferably flat. The adjacent faces of each two adjacent blocks together with the wedge faces 14 and 15 of each of the friction shoes form hollow tetrahedrons adapted to receive the wedging blocks 18.

The mode of operation is as follows:

lVhen pressure is applied to the plungerthis pressure is transmitted to the wedging blocks which tend to slide on the faces 21 of the spreader member, and hence force the friction shoes into frictional engagement with the friction surface 2 of the friction barrel. Owing to the slight inclination of the friction surface 2 the longitudinal movement of the friction shoes is resisted by a rapidly increasing pressure which gives to the device a high capacity. The formation of the wedging faces on the spreader blocks and the shape of the wedge blocks equalize the pressure over the entire exterior surface of the friction shoes and also give a free release action. The operation when pressure is applied to the rear end of the friction barrel is identical to that previously described, the only difference being that the friction mechanism remains substantially stationary and the friction barrel moves with reference to the internal friction mechanism.

Having now described my invention, although it is to be understood that the terms employed have been used in their descriptive and not in their limiting ense, what I claim and desire to secure by Letters Patent is:

1. In a friction draft rigging, the combination with a friction barrel, of a plurality of friction shoes adapted to coact with the said barrel, wedging means for forcing said friction shoes into frictional engagement with the said barrel, said means including a plurality of oppositely arranged pyramidal wedging blocks and a spreader member, said blocks being interposed between the friction shoes and the said spreader member.

2. In a friction draft rigging, the combination with a friction barrel having a tapering interior friction surface, of a plunger member adapted to have a shouldered engagement with the said barrel, cushioning means within the barrel in rear of said plunger, and friction mechanism interposed between said plunger and said cushioning means, said mechanism including a plurality of friction shoes, a plurality of sets of wedging blocks and a spreader member, said member having oppositely disposed wedging faces and being located intermediate of the sets of wedging blocks.

3. In a friction draft rigging, the combination with a friction bar c1, of a plurality of friction shoes having oppositely disposed wedging faces, a wedging means adapted to cooperate with the wedging faces on the said shoes, and spreading means spaced from said shoes and cooperating with said wedging means, said spreading means being provided with a plurality of reentrant angle faces.

4. In a. friction draft rigging, the combination with a friction barrel, of a series of friction shoes each pr vided with a plurality of wedging faces, a plurality of sets of oppositely disposed three-sided wedges, and a spreader member interposed between the sets of wedges and spaced from the said friction shoes.

5. In a friction draft rigging, the com-- bination with a friction barrel, of a plurality of segmental friction shoes each furnished with a wedging face, said shoes being adapted to surround a spreader member, said spreader member having a plurality of pairs of converging faces, eaclr pair of faces in conjunction with the wedging face on the adjacent friction shoe form ing a hollow tetrahedron adapted to receive a correspondingly formed wedge block.

6. In a friction draft rigging, the combination with a surrounding friction barrel, of friction mechanism including a plurality of segmental friction shoes, a plurality of wedge blocks and a wedging member adapt- Copies of this patent may be obtained for ed to be engaged by said wedge block, said wedge blocks being formed as tetrahedrons and being interposed between the friction shoes and said wedging member.

7. In, a friction draft rigging, the combination with a friction barrel, of a spreader member having a? plurality of separated wedging faces, each two adjacent faces forming V-shaped groove, a plurality of friction shoes surrounding said member and means interposed between said spreader member and said friction shoes at opposite ends of the latter for pressing said shoes against the interior of the said barrel.

8, In a friction draft rigging, the combination with a friction member, of a plurality of friction shoes adapted to cooperate therewith, spreading means comprising a member having a plurality of wedge shaped grooves therein, and a plurality of wedges interposed between said spreading means and said friction shoes, each of said wedges being adapted to be received in one of the said grooves in the said spreading means.

9. In a friction draft rigging, the combination with a friction member, of a plurality of friction shoes contacting said friction member, an internal wedging device and a plurality of three-sided wedges interposed between and having wedging engagement with said friction shoes and said internal wedging device.

10. In a friction draft rigging, the 001m bination with a friction barrel, of a centrally disposed wedging member having forwardly and also rearwardly converging wedging faces, a plurality of friction shoes adapted to surround said centrally disposed wedge, and a plurality of sets of wedge blocks interposed between the friction shoes and the said centrally disposed wed e, each wedging block engaging two friction faces on said wedging member.

11. In a friction draft rigging, the combination with a friction barrel, of a centrally disposed wedging member, said memher being provided with a plurality of sets of converging wedging faces, friction shoes surrounding said member and a plurality of tetrahedral shaped friction wedges interposed between said shoes and member, said wedges each engaging a set of said wedging faces.

In testimony whereof I affix my signature.

THOMAS H. SYMINGTON. 

